The invention pertains to portable winch units of the ratchet drum type, and in particular, relates to the ratchet dog employed to transmit force from a hand lever to the winch drum.
In portable winch units such as shown in U.S. Pat. No. 2,501,253, and in the assignee's more recently issued U.S. Pat. Nos. 3,724,816 and 3,727,886, portable winch units are shown which utilize a hand lever to rotate a drum upon which a tension member, such as a cable, is wound. The drum includes a ratchet wheel configuration engagable with a dog or catch mounted upon the hand lever wherein a rotative driving force can be imparted to the drum upon pivoting of the hand lever in a cable tensioning direction. A stop pawl is mounted upon the apparatus frame also engaging the ratchet wheel to prevent rotation of the drum against the tensioning force, and the hand lever ratchet dog, and the stop pawl, are spring biased in a direction toward the ratchet wheel, and may be selectively removed from the ratchet wheel to permit rapid deployment of the cable from the drum.
In that the hand lever mounted ratchet wheel dog is selectively positioned between ratchet wheel engaging and clearing positions, and must be positively maintained in such positions, a variety of operating mechanisms have been proposed for positioning the ratchet dog. Such ratchet dogs must be of high strength, dependable in operation, easily operable, and readily manufacturable. The ratchet dog operating mechanisms of the assignee's above identified patents are improvements over existing ratchet dog operating mechanism, but do not meet all of the requisites of such a ratchet dog to the extent desired.
A simple, yet dependable ratchet pawl of economical construction is shown in use with a wrench in U.S. Pat. No. 635,207, and in such ratchet pawl operation the end of a tension spring is slidably positionable with respect to the pivot point of the ratchet dog to selectively permit the spring to impose a biasing force on the ratchet dog causing the dog to be pivoted in opposite directions. Such an arrangement requires that the spring itself be directly engaged by the operator in order to shift the spring end with respect to the dog, and as the most likely location of engagement of the spring occurs at the coils thereof, the likelihood of pinching exists when shifting the coil spring on the dog. Thus, although this type of ratchet dog biasing mechanism meets several of the desired requisites of pivoted ratchet dogs, the direct engagement of the spring by the operator's finger is objectionable, and a safety hazard.